1. Field of the Invention
The present invention relates to an oil pressure generator for a vehicle such as a motorcycle equipped with a brake lever or a clutch lever in the vicinity of a grip provided on a steering bar handle. More particularly, the present invention relates to an oil pressure generator provided on a handle and configured to operate a hydraulic brake or a hydraulic clutch.
2. Description of the Related Art
A motorcycle is typically equipped with a front wheel which is a steering wheel mounted at a lower portion of a front fork and a rear wheel which is a drive wheel driven by an engine mounted in the motorcycle. The front wheel is rotatably mounted on the front fork provided with a bar handle on an upper portion thereof, and both end portions of the handle form right and left handle grips. A brake device is disposed in the vicinity of the left handle grip, and a clutch device is disposed in the vicinity of the right handle grip.
Conventionally, various hydraulic brake devices have been employed as brake devices for motorcycles. For example, Japanese Laid-Open Patent Application Publication No. H09-58557 discloses a hydraulic brake device. This hydraulic brake device includes an oil pressure generator externally attached to a handle of a motorcycle, and a disc-shaped or drum-shaped hydraulic brake equipped in the vicinity of an axle of a front wheel. The oil pressure generator and the hydraulic brake are connected to each other through a hydraulic hose filled with brake oil.
The oil pressure generator is provided with a master cylinder. A brake lever operated by a rider is mounted to the master cylinder to be pivotable around a base end portion thereof. The master cylinder is substantially tubular, and contains a piston therein. The piston is movable according to an operation of the brake lever performed by the rider. A rubber boot is provided between an outer peripheral surface of the piston and an inner peripheral surface of the master cylinder to seal the master cylinder, thereby inhibiting dust or the like from entering the master cylinder.
As stated above, the conventional oil pressure generator is externally attached to the handle and hence exposed to outside. So, the master cylinder tends to be subjected to dust, rain or wind. Since dust or the like may enter the master cylinder regardless of the presence of the rubber boot, it is desirable to appropriately inhibit such entry of dust or the like. In addition, it is desirable to achieve a lightweight feeling handle by using a lightweight master cylinder that enables a rider to easily operate the handle. Furthermore, it is desirable to provide a vehicle with improved external appearance by lessening exposure of an oil pressure generator to the outside.